1. Field of the Invention
The invention relates to a vertical membrane storage system, and to a method of storing a fluid using the storage system. Specifically, the invention relates to a submerged storage system that is capable of storing any number of fluids, including, inter alia, excess sewage emanating from a sewage system or a combined sewage-storm water system during periods of heavy flow.
2. Background of the Invention
Sewer overflow can cause significant problems, including individual home flooding with sewage, as well as dumping overflow into and consequently polluting local waterways. This overflow occurs when the flow capacity of a sewer system is exceeded by the rainwater in-flow rate into the system for combined sanitary and storm sewer systems. Sewage backup and local water pollution is present in most storm sewer systems where the storm sewers are rarely of a sufficient size to accommodate unusually heavy rainstorms.
When an overflow is encountered, the local municipalities prevent overload of the sewage treatment plant, as well as sewer backup into homes by diverting the excess flow to local waterways, such as rivers, lakes, large retention ponds, and the oceans. This diversion creates an enormous environmental hazard. Moreover, for many inland cities, there are no large natural systems that can accommodate the overflow. As a consequence, these inland cities must rely on very expensive underground storage systems.
To minimize overflow and backup problems from a storm sewer system, a number of expensive methods have been heretofore proposed. Where there are adequate spaces and tax revenues available for doing so, water drainage ponds and lakes have been constructed to collect excess rainwater run-off before the water can gain direct access to the storm sewer system. Such drainage ponds or lakes are usually not feasible. Moreover, recently it has been discovered that such drainage ponds and lakes have created drinking water contamination problems if the area obtains its drinking water from underground wells or streams into which the water in the drainage ponds and lakes can drain.
A municipality also can minimize storm sewer backup and overflow by increasing the size of the storm sewers that make up a citywide storm sewer system. This solution is extremely expensive, however, and it is an impractical solution to the problem, unless the storm sewer system has to be replaced for other reasons.
One costly solution that attempts to solve the problem of sewage backup into an individual""s home is proposed in Regan, U.S. Pat. No. 4,892,440. Regan proposes burying large water storage tanks in the ground to handle the overflow. The water backup system described therein also includes a complicated system of float switches, valves and pumps to both divert the water to the storage tanks, and then to withdraw the overflow from the tanks when the overflow conditions have subsided. Regan""s backup prevention system is quite costly to construct, and once in the ground, cannot readily be moved or replaced. Moreover, it is very expensive to fix leaks that inevitably develop in the storage tanks.
It is known to divert overflow water and sewage to a flexible channel that is capable of expanding when filled with the overflow liquid. For example, German patent application DE 3,426,789 discloses a plastic sack having an opening to receive supply and to discharge overflow sewage water. Overflow still may occur, however, if the plastic sack is not large enough to accommodate the excess flow, and an overflow is provided between the sewer and the plastic sack. In addition, undesirable odor may emanate from the sack because the sewer is in direct contact with the atmosphere. If the overflow capacity of the plastic sack is exceeded, non-clarified sewage still can contaminate the natural waters.
Lesh, U.S. Pat. No. 3,701,428 discloses a sewage disposal unit that comprises a plurality of flexible sewer pipes connected to a flexible plastic septic tank, or tanks, submerged in a body of water adjacent the sewer mains. Lesh states that the pressure of the body of water serves to support the submerged plastic septic tanks which avoids extensive excavation or building concrete tanks. The flexible system of Lesh is limited in size, and when its capacity is exceeded, overflow will still occur.
Clemens, WO 98/03742 proposes another flexible channel for storing sewage and clarifying the sewage in the event of heavy rainfall. Clemens utilizes a flexible plastic material, such as a geotextile (Perl E), and tension ropes to support the flexible material when filled. While providing a cheaper and more mobile solution to the overflow problem than that proposed in Regan, Clemens"" system does not effectively clarify the sewage, and it is difficult to fill and withdraw liquid from the system. The tension ropes also cause considerable stress at the junction of the tension ropes and the plastic material that can cause rips or tears. The tension ropes also may cause the deposit of excess sludge that is difficult to remove.
In addition to the pollution problems associated with overflow of sewage, there are other significant environmental problems associated with the earth""s natural water system. It is generally accepted that our oceans are losing life. Les Watling of the University of Maine has hours of videotape showing xe2x80x9cbefore-and-afterxe2x80x9d footage of the ocean, and the effects of trawling: showing gardens of life in one segment (before), and mud and debris in the other (after).
In vast near-coastal areas and in semi-enclosed seas the water itself has been rendered sterile. The problem is believed to be caused by nutrient pollution, the smothering deluge of sewage, manure, and chemical fertilizers from land-based activities. Rising populations and the increasingly intensive agriculture and livestock operations needed to feed them have caused an explosion in nutrient run-off. This problem is even more exacerbated by the dramatic increase in bio-engineered fertilizers and feedstocks, which are now dumping numerous unknown organisms into our waters. Although some nutrients can be beneficial to our waters, too large a quantity poisons the waterways. Phyloplankton productivity is limited by the availability of nutrients in sea water, and where there are excessive levels, these microscopic algae explode in such massive blooms that grazers cannot keep up. The dead algae fall to the bottom to be decomposed by bacteria, a process that consumes large amounts of oxygen, so much that often little or none is left to sustain anything else. This condition is called hypoxia. When hypoxic conditions occur, all animal life that cannot swim away suffocates. This is how the Black Sea""s shallow life-bearing shelves were laid waste, setting the stage for the ecological collapse of the entire basin. Hypoxia also has become a chronic problem in the Gulf of Mexico, where a seven thousand square mile xe2x80x9cdead zonexe2x80x9d appears off the Louisiana and Texas coasts during the spring and summer, disrupting shrimp and fish migrations, and wiping out bottom fauna. Seasonal hypoxia affects many other natural waterways, including, for example, the Chesapeake Bay, New York Bight, the Adriatic, North, and Baltic Seas, the Yellow Sea, and the like.
Other pollution exists as well. For example, toxic chemicals have for years been dumped into our vast oceans. Paints used on ships to keep barnacles and other parasites from clinging to the ship""s hulls become dissolved in the water and ingested by the local marine life. Moving marine life from one ecosystem to another also creates a great deal of pollution.
The most common agents of what scientists call xe2x80x9cinvasive species transferxe2x80x9d are oceangoing tankers and container ships. When light on cargo, most ships are obliged to pump water into their holds to maintain their seaworthiness. This ballast water contains numerous plants and animals, some as adults, but most in the form of eggs, larvae, or juveniles. On reaching its destination halfway around the world, a ship then will discharge some or all of its ballast water and, in the process, introduce huge numbers of alien species to the surrounding environment. Worldwide, the National Research Council estimates that three thousand species are picked up in ballast water every day. The species that survive the lengthy trip, and then the new environment become established. Lacking natural predators or having overwhelming advantages over their prey, some intruders completely take over, exterminating competitors and turning the ecosystem upside down.
The expression xe2x80x9cinvasive species transferxe2x80x9d denotes living plants, animals or bacteria that have accidentally or purposefully been introduced into a new habitat and have the potential to devastate the native plants, animals, and organisms, or to create ecological monsters like zebra mussels, lampreys, Asian snails, European crabs (green), and the bright green sea grass (Caulerca Taxifola), which is toxic to all organisms that attempt to ingest it. Other examples include the Mnemiopsis Leidyl (comb jellyfish), a benign native of the Northeastern United States, which have killed most living things in the Black Sea.
Many microscopic spores, eggs, animals, etc. that are transferred by the bilge and ballast water are benign, especially when compared to the Pfiesteria Piscicida (fish killer) that can metamorphose into 24 different beings, most of which are capable of devouring most living things. Although these xe2x80x9cmorphsxe2x80x9d are microscopic, they are dangerous even to mankind. They are partial also to sewage, blood and offal from slaughterhouses for chickens, hogs, cattle, and horses. These fish killers also can kill a fish from a distance of three or four feet and dissolve it simultaneously.
These invasive species transfer invasions are becoming increasingly commonplace as ships become larger and more numerous. San Francisco Bay, a busy shipping port, is home to at least 212 exotic species. The fish population is now a bizarre mix of Mississippi catfish, East Asian gobies, Japanese carp, and aquarium goldfish. The bottom is controlled by Chinese mitten crabs (which can harbor human parasites and whose burrowing causes levees to collapse) and Asian clams (which filter out virtually all plankton, starving out native fish). A new species takes hold in the Bay every twelve weeks on average. Exotic invaders tend to wreak the most havoc in ecosystems already damaged by other stresses. A North American bristle worm now dominates the bottom of Poland""s highly polluted Vistula lagoon.
Another increasing source of pollution in our vast waterways is caused by oil spills, as well as oil and fuel leaks from seaworthy vessels. While the massive oil spills, like the Exxon Valdez, provide an immediate and glaring source of pollution, waste from oil ships has been a problem for a considerable time. It is not possible under present stringent regulations for ships to deposit bilge water, or other water that may contain oil into the ocean or other waterways. Thus, oil-water mixtures must be disposed of directly in public sewers or waterways in view of their oil content. Furthermore the recovery value of the oil in the water is quite small.
Propp, U.S. Pat. No. 4,048,070 describes a system that provides a holding tank for the wastewater received from ships. The holding tank is attached to a series of decantation tanks, which in turn are connected to separator tanks. The system of Propp is very expensive and difficult to construct and employ.
Other forms of contamination of natural or man-made waterways can come from fish farms. Nearly 20% of the fish and seafood consumed today now is raised on farms even from seed, fingerlings, very young mollusks or eggs that are raised on commercial feed formulated to provide adequate nutrients or on natural food organisms grown through water fertilizing techniques. Because potentially polluting and disease-bearing waste accumulates in any fish farm, it must be disposed of through elaborate water circulation systems and filtration. Some filtration systems harness bacteria that convert ammonia, which the fish secrete through their gills into nitrates. It would be desirable to provide a fish farming system that did not require such complicated and expensive disposal systems.
Finally, many impoverished nations do not have adequate drinking water, and do not even have an adequate sewage disposal system. Sewage is dumped directly into the water that is ultimately used for drinking, causing dysentery, cholera, and many other bacterial and viral diseases. Effectively treating the sewage not only may solve the drinking water problem, but also may provide fertilizer to assist growth of vegetation, rice, and other staple goods.
There is a need to solve the pollution problems noted above. For example, there is an increasing need to provide a solution to the overflow of sewage into natural waterways. There also exists a need to alleviate, ameliorate, or completely eliminate the problems associated with invasive species transfer. There also exists a need to prevent the unnecessary pollution caused by oil spills and/or excess oil or fuel spillage into the natural waterways. Finally, it would be desirable to provide a means by which people living in impoverished nations could be supplied with clean drinking water, and to provide a mechanism to treat the waste sewage.
It is therefore a feature of an embodiment the present invention to provide a vertical membrane storage system including a flexible membrane housing having an upper enclosed portion capable of storing a fluid, and a lower open portion for receiving the fluid. The storage system also includes a flotation tube disposed above and connected to the upper enclosed portion, and an anchor having receiving means for receiving a fluid disposed concentrically therein, whereby the anchor is connected to and encloses the lower open portion of the flexible membrane.
In accordance with another feature of an embodiment of the invention, there is provided a submerged overflow storage system comprising at least one vertical membrane storage system as described above. The submerged overflow storage system also includes an inflow pipe connected to the receiving means of the at least one vertical membrane storage system, an inflow overflow valve disposed within the inflow pipe, an outflow pipe connected to the inflow pipe, and an outflow valve disposed within the inflow pipe and the outflow pipe.
It is an additional feature of an embodiment of the present invention to provide a method of storing a fluid that includes injecting a fluid into the above-described vertical membrane storage system via the receiving means. It is an additional feature of an embodiment of the invention to provide a method of preventing invasive species transfer comprising emptying ballast and/or bilge water from a sea-going vessel into the above-described submerged overflow storage system.
These and other features of the invention will be readily apparent to those skilled in the art upon reading the description of preferred embodiments that follows.